IL6 is an interleukin that acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine. It is capable of crossing the blood-brain barrier and initiating synthesis of PGE2 in the hypothalamus, thereby changing the body's temperature setpoint. It can be secreted by macrophages in response to specific microbial molecules, referred to as pathogen-associated molecular patterns (PAMPs). These PAMPs bind to an important group of detection molecules of the innate immune system, called pattern recognition receptors (PRRs), including Toll-like receptors (TLRs). These are present on the cell surface and intracellular compartments and induce intracellular signaling cascades that give rise to inflammatory cytokine production.